Typical external combustion systems such as combustors and boilers may include relatively complicated systems to maximize the extraction of heat from a heated gas stream. Generally, such systems may rely on forced or natural convection to transfer heat from the heated gas stream through heat transfer surfaces to heat sinks.
Other systems, which may include the combustion systems indicated above, or may include other systems such as turbo-jet engines, ram- or scram-jet engines, and rocket engines, for example, are limited with respect to combustion temperature or reliability due to erosion of critical parts by hot gases. It would be desirable to reduce heat transfer to temperature-sensitive surfaces of such systems.